Inhibiting photocatalytic electron-hole recombination by coupling MIL-125 (Ti) with chemically reduced, nitrogen-containing graphene oxide

Abstract

In this study, we fabricated a novel chemically reduced nitrogen containing graphene oxide (CR-N-GO) modified metal organic framework, (MIL-125(Ti)) by one-pot solvo-thermal approach for its application in photocatalytic degradation of xenobiotic organic pollutants. CR-N-GO has nitrogen present as impurity on its surface therefore, aim of this study was to signify the importance of that nitrogen for enhancement of visible light activity of photocatalyst. The r-N-MIL (modified MIL-125(Ti)) photocatalyst was characterized to obtain structural, optical, and surface properties. This characterization suggests mesoporous structures with improved surface roughness and visible light capturing property. Photocatalytic degradation of Rhodamine B (RhB) increased 2.0-fold under visible light compared to that of the pristine MIL-125(Ti). Enhanced photocatalytic activity under visible light was attributed to p states induced by oxygen bonding of MIL-125(Ti) oxo clusters with CR-N-GO, nitrogen incorporation into MIL-125(Ti) from CR-N-GO, localized electronic states of Ti-O-C bonds and mesoporous structure. Moreover, photoexcitation, radical generation, and photocatalytic degradation steps exhibited the photocatalytic degradation mechanism. Furthermore, LC/MS analysis identified chromophore cleavage, ring opening, and mineralization as major photocatalytic degradation pathways. Performance evaluation through catalyst surface efficiency and apparent quantum yield is on par with those of other catalysts and describes r-N-MIL as a fascinating semiconductor photocatalyst.